Is A42 a billable ICD-10-CM code?

No. A42 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does A42 sit in the tabular list?

Certain infectious and parasitic diseases (A00-B99), in the block Other bacterial diseases (A30-A49).

What cannot be coded together with A42?

A42 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

A42

A42 — Actinomycosis

Non-billable headerICD-10-CM

A42 is a non-billable header ICD-10-CM code for actinomycosis. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

actinomycetoma (B47.1)

Other codes that can never be billed with A42

These codes carry an Excludes1 note pointing at A42. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading A42 alone.

J17Pneumonia in diseases classified elsewhere

Risk adjustment

A42 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code to one of these instead A42

6 child codes. Green means billable.

Questions about A42

Is A42 a billable ICD-10-CM code?: No. A42 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does A42 sit in the tabular list?: Certain infectious and parasitic diseases (A00-B99), in the block Other bacterial diseases (A30-A49).
What cannot be coded together with A42?: A42 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.